摘要
以FeSO_4·7H_2O、H_3PO_4、H_2O_2、NaOH为原料,通过连续的氧化沉淀法一步制得类球形非晶态的FePO_4·2H_2O。将FePO_4·2H_2O与一定浓度的H3PO4溶液混合,在80～95℃陈化2 h,制得结晶完好具有微纳米结构的FePO_4·2H_2O前驱体。由该FePO_4·2H_2O制得的LiFePO_4正极材料具有优异的性能:0.1 C时首次充放电比容量分别为169.0和164.9 mAh/g,首次库仑效率为97.6%,1 C和10 C时可逆放电比容量分别大于150和100 mAh/g,具有良好的倍率性能和循环性能。用X射线衍射仪和扫描电镜等对FePO_4·2H_2O和LiFePO_4的结构和形貌进行表征。该方法可显著降低FePO_4·2H_2O前驱体制备所需原料消耗和成本,精确调控Fe/P摩尔比,同时适于连续规模生产,也十分有利于环保。
Spherical amorphous FePO4·2 H2O powders were synthesized by continuous oxidizing precipitation method,using FeSO4·7 H2O,H3PO4,H2O2 and NaOH as the raw materials.The amorphous FePO4·2 H2O powders were mixed with H3PO4 solution and aged at 80-95℃for 2 h.The crystalline state FePO4·2 H2O with“micro-nano-structure”were obtained after aging crystallization.Using the FePO4·2 H2O powders as the precursors,the prepared LiFePO4 cathode materials show excellent electrochemical performance.At current density of 0.1 C,the cathode materials'initial charge and discharge specific capacity are 169.0 and 164.9 mAh/g,respectively.The initial coulomb efficiency is 97.6%.At current of 1.0 C and 10 C,the reversible specific capacity is higher than 150 and 100 mAh/g,respectively.The materials show excellent rate capability and cycling performance.The structure and morphology of FePO4·2 H2O and LiFePO4 were characterized in detail by XRD and SEM.The raw materials and cost for the preparation of prepare FePO4·2 H2O precursors could be obviously decreased by this method.The Fe/P molar ratio of FePO4·2 H2O precursors could be controlled accurately.This method was suitable for large scale production of FePO4·2 H2O precursors continuously and environment-friendly.
作者
孙少先
应皆荣
SUN Shao-xian;YING Jie-rong(Department of Materials Science and Engineering,Chang'an University,Xi'an Shanxi 710064,China;Institute of Materials and Chemical Engineering,Ningbo University of Technology,Ningbo Zhejiang 315211,China)
出处
《电源技术》
CAS
CSCD
北大核心
2018年第10期1473-1476,共4页
Chinese Journal of Power Sources
基金
宁波市自然科学基金项目(2010A610143)
